There is only one issue that matters: is Tony Blair an electoral liability?

It is necessary to sweep aside the red herrings, those events that seem more important than they really are

A few words stand out in the torrent of reports and interviews on the Prime Minister's future. Tony Blair delivered them himself. Apart from these words, a single sentence, nothing else matters: not the summit between Gordon Brown and John Prescott in the car park of an oyster bar, not Mr Prescott's declaration that the tectonic plates are moving, not the persistent expressions of cabinet support for Tony Blair, not even Mr Brown's ambitions to be PM. We will come to the striking prime ministerial words shortly. First it is necessary to sweep aside the red herrings, those events and individuals that seem more important than they really are.

Let us begin with the Cabinet - after all that is where it ended for Margaret Thatcher when she lost the support of her top ministers. Currently cabinet members compete to declare their public support for Mr Blair's continuing premiership. They express more or less the same views privately as well. He will carry on. He should carry on. What is more, they mean it. As I argued a couple of weeks ago, the idea that Mr Blair has lost the support of the Cabinet or that we are witnessing the return of cabinet government is fanciful. Ministers are in their privileged positions because the Prime Minister appointed them. Unlike their counterparts in the 1960s and 1970s they do not have power bases in the Labour Party. Not surprisingly they are unsure what would happen to them under another leader.

These loyal ministers are also caught in a trap. If they do not agree to go on programmes to declare their support for Mr Blair all hell would break loose. "Cabinet deserts Blair" we would scream. But when they queue up to express their support they add to a sense of crisis. I have long believed that the vast number of media outlets in Britain that report domestic politics heightens a sense of crisis. Still that is where we are.

The cabinet ministers and the rest of us are stuck with it. Although they are trapped into increasing the political temperature they will not call for Mr Blair to resign publicly or privately.

What of the only cabinet minister to wield immense power? Nobody doubts that Gordon Brown wants the top job, but he is not orchestrating the current destabilising headlines, a magician waving a malevolent wand somewhere in a Treasury bunker. Indeed I suspect he is alarmed by some of the stories. At the moment the Chancellor has three priorities. The first and broadest is to ensure that Labour wins another big majority whoever is in charge at the time of the election. The second is to agree on an election manifesto with which he is happy. The third and most immediate is to finalise the comprehensive spending review that will be unveiled in July. Of course these priorities are shaped on the assumption that at some point he will inherit the leadership. He seeks to have something worth leading. But both Mr Blair and Mr Brown are tribal politicians in the sense that they yearn to defeat the Conservatives heavily again. Mr Brown wants Labour to win big whether he or Mr Blair is at the helm at the next election. The worst that can be said of Mr Brown is that he is keeping his head down, getting on with things, waiting on events.

Probably John Prescott wishes he had kept his head down too. He can have the same impact as Corporal Jones in Dad's Army. When the Deputy Prime Minister cries "Don't panic!" the entire Government panics.

The aim of his well-publicised weekend interview was to calm everyone down, the Blairite outriders and ambitious Brownites. Mr Prescott wanted to say that just because the tectonic plates were moving that should not be an excuse for destabilising activity. Tony would go when he wanted to go. As he should have realised the attention focused on those tectonic plates.

Mr Prescott and Mr Brown talk to each other fairly often, not just in the car park of an oyster bar in Scotland. These are busy men, but their lives are not so frantic that their only chance for a conspiratorial exchange is in a car park. For at least two years they have discussed the prospects for a smooth succession. Mr Prescott wants Mr Brown to inherit the leadership at some point. He resolved long ago to stay in post to bring this about.

But if Mr Prescott seeks a smooth succession he is hardly going to surface from an oyster bar and knife Blair in the back.

More significant is the overlooked section in his weekend interview in which he attacked some Blairites for implicitly condemning ministerial attempts to improve the public services: "Their criticism of existing policies has undermined public support for the government." Mr Brown is known to hold precisely the same view. Evidently they fume together, but this does not mean they are planning a coup from their oyster bar car park.

We are so used to seeing political crises through the Blair/Brown prism that nothing else in British politics seems to matter very much. After 11 September 2001, when Mr Blair toured the world, it was viewed here partly as bad news for Mr Brown. I almost expected to read the headline "Setback for Brown as planes hit World Trade Centre". Similarly when the Prime Minister is in trouble we imagine a triumphant Chancellor planning his first Cabinet.

The current crisis is not like that. It is not about Mr Brown, Mr Prescott, the Cabinet or restive MPs.

The striking words, the ones that matter, are these: Blair has let it be known he would stand down if he were to become an electoral liability. Evidently he is convinced he is not one and will not become one, but the prime ministerial comment conveys what this is all about.

Questions about Mr Blair's future would rage even if Mr Brown did not exist and Mr Prescott was nowhere to be seen. In advance of the war, Mr Blair said he would get a second United Nations resolution, predicted that WMD would be found, insisted that Saddam posed a growing threat and conjured up a picture of liberated Iraqis expressing their gratitude to the United States and Britain.

Any leader's future would be in doubt after such a calamitous record of misjudgement. Indeed I am surprised that some in the media is still surprised about the speculation, detecting a Brownite conspiracy.

Whether or not this makes Mr Blair an electoral liability is another matter. Obviously he is helped hugely by the fact that the Conservative leadership supported him along the way. But unless Iraq calms down the entirely legitimate questions about his judgement and the political calculations that brought them about will not subside. It will be interesting to hear Mr Blair's definition of what constitutes "an electoral liability" and what precisely he meant yesterday when he resolved with apparent clarity to get the "job done" in Iraq.

This is much bigger than speculation about what sort of Prime Minister Mr Brown would make, or what was said in a car park. It is about Mr Blair and Iraq, no other politician and no other issue.

s.richards@independent.co.uk